HPV-based Screening Could Reduce Burden on Women, Clinicians

In a large-scale study, a single human papillomavirus (HPV) screening was clearly superior to cytology in predicting a woman’s risk of developing cervical cancer in a large-scale trial, presented at the Cancer Prevention and Epidemiology Oral Abstract Session (Abstract 1508).

The results suggest that women who are HPV-negative could safely be screened at a 5-year interval, reported Hormuzd A. Katki, PhD, of the National Cancer Institute. Dr. Katki noted that, although current American Cancer Society and American College of Obstetricians and Gynecologists guidelines allow co-screening with HPV and Pap testing every 3 years, this recommendation has not been widely accepted in clinical practice. A recent phone survey found that only approximately 19% of physicians are recommending a 3-year interval for women who are HPV and Pap negative, he said.

“This implies that there are a lot of concerns about the safety of these guidelines in routine clinical practice,” Dr. Katki said. The study he presented, which was done in collaboration with Kaiser Permanente Northern California, addressed the question of how coscreening works.

In the trial, 331,818 eligible women age 30 and older received both HPV and Pap smear testing between 2003 and 2005 and were followed through 2009. The women were categorized based on results of baseline HPV and Pap tests, and investigators calculated 5-year cumulative rates of cancer and precancer (Fig. 1). Precancer was defined as cervical intraepithelial neoplasia of grade 3 (CIN3).

Women testing negative for HPV had an extremely low 5-year risk of cervical cancer, Dr. Katki said. The risk was not appreciably lowered by a negative Pap test. “This suggests that HPV-negative women could return for screening no earlier than 3 years,” Dr. Katki said.

In women testing positive for HPV, the Pap test provided further information. In HPV-positive women, an abnormal Pap test indicated an increased risk of cervical cancer or precancer development and suggested that disease may be immediately present. A normal Pap test, on the other hand, indicated that cervical cancer or precancer, if it occurred, would more likely occur in the future.

In this way, Pap testing could be used to triage HPV-positive women, Dr. Katki explained.

The study found that HPV-negative women had a low 5-year cancer risk (3.8 per 100,000 women per year), similar to women who were both HPV-negative and Pap-negative (3.2 per 100,000 women per year; p = 0.8), and half the risk of women who were Pap-negative (7.5 per 100,000 women per year; p = 0.3).

The discussant of the paper, Eva Szabo, MD, of the National Cancer Institute, said the study addresses an important question. “It really provides support for 3-year screening of HPV-negative women and suggests that you can drop the Pap smear and rely on HPV testing. In other words, you can do less, which frankly, is not how medicine usually goes; usually we do more.”

The study is “potentially practice-changing and resource-saving,” Dr. Szabo said. However